Power transfer units (PTUs) are used in some vehicles to distribute driving torque provided from an engine and transmission to the right front wheel and both rear wheels of a vehicle. In some other arrangements the right side half shaft passes through the PTU and is not considered part of the PTU. For example, some power transfer units only transfer torque from a transverse transmission differential to a propeller shaft, which then drives rear half shafts through a rear differential. A hypoid gear set is often used to accomplish the 90 degree turn in the direction of drive between the front differential carrier axis of rotation and the propeller shaft axis of rotation. The torque ratio that the hypoid gear set can provide is dependent on the relative tooth counts of the hypoid ring gear and the pinion gear. The diameters of these gears are limited by available packaging space.